Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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INTUMESCENT COATING COMPOSITION
The present invention relates to an intumescent coating composition, to a
method for
coating a substrate with said composition, to a substrate coated with said
composition, to
an article comprising said substrate and to a method to provide fire
protection for a battery
and/or an article comprising a battery in particular a vehicle comprising a
lithium ion
battery.
Background of the Invention
Commercial intumescent coating compositions generally contain considerably
high
amounts of TiO2 as an important component to obtain the desired fire
protection and
mechanical characteristics of the cured coating in particular char strength
with the result
that the resultant cured coatings are generally white or off white and cannot
be easily
tinted. Since these intumescent compositions were generally used for fire
protection in
construction applications this was so far not considered as draw back.
Batteries have long been used as mobile power sources. In particular the
development of
lithium ion batteries has led to an increased power density. As a result, the
use of lithium
ion batteries has become wide spread in a variety of applications, including
consumer
electronics particularly mobile phones, tablet and laptop computers, medical
devices,
industrial equipment, and in particular hybrid/electrical vehicles.
However, many batteries and particularly lithium ion batteries are vulnerable
to thermal
runaways during which heat and gas are rapidly discharged from a battery and a
fire
hazard is created. Batteries, especially lithium ion batteries, may comprise
electrolyte
compositions that contain combustible organic solvents that add to the fire
hazard
associated with batteries, in particular lithium ion batteries. Furthermore,
the batteries used
in the above exemplified applications are predominantly battery packs
comprising a
plurality of individual battery cells. Lithium ion batteries for hybrid or
electric vehicles
like cars, busses and trucks may contain thousands of individual battery
cells. A thermal
runaway may be caused by manufacturing defects, accumulation of heat, internal
short
circuits, or external impacts or trauma. A thermal runaway in one battery cell
may affect
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adjacent battery cells leading to an uncontrollable chain reaction with the
result that the
entire battery pack may catch fire which in case of vehicles comprising those
batteries
may spread over the entire vehicle putting the drivers and passengers at risk.
Recent incidents with cell phones or electric cars catching fire due to a
thermal runaway of
the battery pack make it evident that there is a need to provide better fire
protection for
batteries, battery cells as well as apparatuses comprising said batteries such
as mobile
phones, tablet or laptop computers and hybrid or electric vehicles and for
their users.
Therefore, intumescent coating compositions might be useful to provide fire
protection for
batteries and articles comprising batteries, particularly lithium ion
batteries.
Compared to intumescent coating compositions hitherto used in construction
applications
in addition to provide fire protection additional requirements might be
important for
intumescent coating compositions that are useful in battery applications.
Since these
coating compositions are intended to be used to provide fire protection to
consumer
products like cell phones, tablet or laptop computers or cars there is a
desire in the
industry that the color of the coating is not limited to white or off white,
i.e. that the
intumescent coating compositions can be tinted to provide a wide range of
appealing
colors in particular black and can be formulated to provide the desired gloss
in particular
high gloss coatings without compromising the fire protections and mechanical
properties
of the cured intumescent coating.
Furthermore, the above discussed articles to be protected against battery
fires are mobile
articles and therefore might be subjected to mechanical shock or impact. Thus,
there is a
desire in industry for intumescent coating compositions that exhibit improved
impact
resistance of the cured coating.
In addition, the above-mentioned articles or battery cases for said articles
can be made of
aluminum or may comprise aluminum parts with the result that the intumescent
coating
compositions are intended to be applied onto aluminum substrates. Therefore,
there is a
further desire in industry for intumescent coating compositions that exhibit
improved
adhesion of the cured coating to aluminum substrates.
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Thus, according to a general aspect it is an object of the present invention
to provide an
intumescent coating composition that meets one or more of the above discussed
desires in
industry.
Summary of the Invention
This and other objects have been attained by an intumescent coating
composition
comprising:
(a) a resin component comprising
- (al) a polyepoxy-functional compound and
optionally;
- (a2) a beta-hydroxy ester of (meth)acrylic acid; and/or
- (a3) a (meth)acrylate-functional compound different from compound
(a2);
(b) a crosslinker component comprising at least one compound (bl) bearing a
plurality
of functional groups that are reactive with the epoxy groups of the polyepoxy-
functional compound;
(c) 5 to 20 wt.-% based on the total weight of the intumescent coating
composition of
an organo silane compound selected from organo silane compounds of formula (I)
or (ii) and combinations thereof
(I),
(Y - L)õ ¨ B ¨ (K - (II)
wherein:
- n and m are integers from 1 to 3 and o is an integer from
0 to 2, wherein n + m + o is 4;
- y is an integer from 1 to 3 and w is an integer from 0 to 2, wherein y +
w is
3;
- u is an integer of at least 1 and z is an integer of at least 2;
- B is a polyvalent organic group, wherein the valency of B is u + z;
L is a divalent organic group or a bond if Y is a vinyl group;
- K is a divalent organic group or a bond.
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- Y- is a functional group reactive with the epoxy groups and/or the
(meth)acrylate groups if present of component (a) or the functional groups
of component (b);
- X is independently selected at each occurrence from chloro, alkoxy,
acyloxy and oximino; and
- R is a hydrocarbyl group;
(d) a compound providing an expansion gas upon thermal decomposition;
wherein
the compounds as defined for (a) to (d) differ from each other, wherein
the intumescent coating composition is liquid at 23 C and atmospheric pressure
and
comprises less than 5 wt.-% based on the total weight of the composition of
water.
The present invention further relates to a method for coating a substrate
comprising
applying the intumescent coating composition according to the present
invention at least
partially to a substrate and optionally curing the applied coating
composition.
According to a further aspect, the present invention is directed to a
substrate coated by
said method and to an article comprising said substrate.
According to a still further aspect, the present invention is directed to the
use of the
intumescent coating composition according to the present invention
- to provide fire protection for a battery or a battery case and/or to
reduce or prevent
thermal runaway of a battery or a battery case when applied to any part of the
battery or the battery case; or
to provide fire protection for an article comprising a battery when applied to
a part
of the article adjacent to the battery between the battery and the article,
wherein the battery is suitably a lithium ion battery.
According to a still further aspect, the present invention is directed to a
method to provide
fire protection to a battery or to reduce or prevent thermal runaway of a
battery by
applying the curable intumescent coating composition as defined according to
the present
invention to any part of the battery to form a coating thereon and curing the
coating to
obtain a crosslinked intumescent coating thereon.
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According to a still further aspect, the present invention is directed to a
method to provide
fire protection for an article comprising a battery by applying the curable
intumescent
coating composition as defined according to the present invention to a part of
the article
adjacent to the battery between the battery and the article to form a coating
thereon and
curing the coating to obtain a crosslinked intumescent coating thereon. In
particular the
article may be a vehicle comprising a lithium ion battery and a passenger
cabin and the
crosslinked intumescent coating is positioned to protect the passenger cabin
of the vehicle
from a battery fire.
Description of the Drawings
Figure 1 is a graph showing the thermal transfer of heat through an exemplary
intumescent
coating of the present invention over time.
Figure 2 is a graph showing the thermal transfer of heat through an exemplary
intumescent
coating of the present invention over time.
Figure 3 is a graph showing the thermal transfer of heat through an exemplary
intumescent
coating of the present invention over time.
Figure 4 is a graph showing the thermal transfer of heat through several
exemplary
intumescent coatings of the present invention over time.
Detailed Description of the Invention
Other than in any operating examples, or where otherwise indicated, all
numbers
expressing quantities of ingredients, reaction conditions and so forth used in
the
specification and claims are to be understood as being modified in all
instances by the
term "about." Accordingly, unless indicated to the contrary, the numerical
parameters set
forth in the following specification and attached claims are approximations
that may vary
depending upon the desired properties to be obtained by the present invention.
At the very
least, and not as an attempt to limit the application of the doctrine of
equivalents to the
scope of the claims, each numerical parameter should at least be construed in
light of the
number of reported significant digits and by applying ordinary rounding
techniques.
Notwithstanding that the numerical ranges and parameters setting forth the
broad scope of
the invention are approximations, the numerical values set forth in the
specific examples
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are reported as precisely as possible. Any numerical value, however,
inherently contain
certain errors necessarily resulting from the standard deviation found in
their respective
testing measurements.
.. Also, it should be understood that any numerical range recited herein is
intended to
include all sub-ranges subsumed therein. For example, a range of "1 to 10" is
intended to
include all sub-ranges between (and including) the recited minimum value of 1
and the
recited maximum value of 10, that is, having a minimum value equal to or
greater than 1
and a maximum value of equal to or less than 10.
As used in this specification and the appended claims, the articles "a," "an,"
and "the"
include plural referents unless expressly and unequivocally limited to one
referent. For
example, although reference is made to "a" polymer, "a" curing agent", "a"
carbon source,
"a" foaming agent, "an" acid source, "a" reinforced fiber, "an" inorganic
additive, "a"
.. coating composition and the like, one or more of any of these components
can be used.
The term "hydrocarbyl" herein refers to a group comprising carbon and hydrogen
atoms.
The term "long chain hydrocarbon substituent" herein refers to a hydrocarbyl
having at
.. least 6 carbon atoms.
The term "battery" as used herein throughout the claims and the specification
refers to an
individual battery cell as well to a battery pack comprising a plurality of
battery cells.
According to a general aspect of the present invention the intumescent coating
composition comprises:
(a) a resin component comprising
- (al) a polyepoxy-functional compound and
optionally;
(a2) a beta-hydroxy ester of (meth)acrylic acid; and/or
- (a3) a (meth)acrylate-functional compound different from compound
(a2);
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(b) a crosslinker component comprising at least one compound (bl) bearing a
plurality
of functional groups that are reactive with the epoxy groups of the polyepoxy-
functional compound;
(c) 5 to 20 wt.-% based on the total weight of the intumescent coating
composition of
an organo silane compound selected from organo silane compounds of formula (I)
or (ii) and combinations thereof
(I),
(Y - L)õ ¨ B ¨ (K - SiX,R,,)z (II)
wherein:
- n and m are integers from 1 to 3 and o is an integer from
0 to 2, wherein n + m + o is 4;
- y is an integer from 1 to 3 and w is an integer from 0 to 2, wherein y +
w is
3;
u is an integer of at least 1 and z is an integer of at least 2;
- B is a polyvalent organic group, wherein the valency of B is u + z;
- L is a divalent organic group or a bond if Y is a vinyl group;
- K is a divalent organic group or a bond.
- Y comprises a functional group reactive with the epoxy groups and/or the
(meth)acrylate groups if present of component (a) or the functional groups
of component (b);
- X is independently selected at each occurrence from chloro, alkoxy,
acyloxy and oximino; and
- R is a hydrocarbyl group;
(d) a compound providing an expansion gas upon thermal decomposition;
wherein
the compounds as defined for (a) to (d) differ from each other, wherein
the intumescent coating composition is liquid at 23 C and atmospheric pressure
and
comprises less than 5 wt.-% based on the total weight of the composition of
water.
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Resin Component (a)
The polyepoxy-functional compound (al) is not particularly limited. It
includes, but is not
limited to oligomeric or polymeric compounds bearing a plurality of epoxy
functional
groups, for example epoxy resins.
Suitable epoxy resins for the resin component (al) comprise at least one
polyepoxide. The
polyepoxide has at least two 1,2-epoxy groups. Usually the epoxy equivalent
weight of the
polyepoxide ranges from 80 to 6000, typically 100 to 700. Epoxy compounds can
be
saturated or unsaturated, cyclic, aliphatic, alicyclic, aromatic or
heterocyclic. They may
comprise substituent(s), such as halogen, hydroxy, and ether groups.
The examples of polyepoxides are, for example, polyglycidyl ether of
polyphenols, such
as 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), resorcinol, hydroquinone,
benzenedimethol, phloroglucinol, bisphenol F, and catechol; or polyglycidyl
ether of
polyols, such as alicyclic polyols, such as 1,2-cyclohexane diol, 1,4-
cyclohexane diol, 2,2-
bis(4- hydroxycyclohexyl)propane, 1,1-bis(4-hydroxycyclohexyl)ethane,
2-methyl- 1,1-
bi hydroxycyclohexyl)propane, 2,2-bis(4- hydroxy-3-tert-
butylcyclohexyl)propane,
1,3-bis(hydroxymethyl)cyclohexane and 1,2-bis(hydroxymethyl)cyclohexane. The
examples of aliphatic polyols include, in particular, trihydroxymethylpentane
diol,
ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol,
1,4-
butyleneglycol, 1,5-pentanediol, 1,2,6-hexanetriol, cyclohexanedimethanol,
glycerol,
thrimethylolpropane, hydrogenated bisphenol A, hydrogenated bisphenol F or
polyether
glycols, for example, poly(oxytetramethylene) glycol, poly(oxyethylene)
glycol,
poly(oxypropylene) glycol and neopentane diol.
A particular suitable polyepoxide has an epoxy equivalent weight of less than
300
g/equivalent. The example includes EPON 828, which is commercially available
from
Hexion Inc.
Another group of suitable epoxy resins include polyglycidyl ethers of
polycarboxylic
acids, formed by the reaction of an epoxy compound such as epichlorohydrin
with an
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aliphatic or aromatic polycarboxylic acid such as oxalic acid, succinic acid,
glutaric acid,
terephthalic acid, 2,6-napthalene dicarboxylic acid, or dimerised linoleic
acid.
Other suitable epoxy resins that can be used according to the present
invention comprise
epoxidized olefinically unsaturated alicyclic materials such as epoxy
alicyclic ethers and
esters, epoxy resins containing oxyalkylene groups, epoxy novolac resins,
which are
prepared by reacting an epihalohydrin with the condensation product of an
aldehyde with
a monohydric or polyhydric phenol such as epoxy phenol novolac resins or epoxy
cresol
novolac resins.
1()
Furthermore, it can be advantageous according to the present invention to
employ a
flexible polyepoxide resin as polyepoxy-functional compound (al) of the
intumescent
coating composition of the present invention. These resins are generally
essentially linear
materials, although a small amount of branching is tolerated. Exemplary of
suitable
materials are epoxidized soybean oil, dimer acid-based materials such as EMPOL
1010
resin, which is commercially available from BASF SE, Ludwigshafen Germany and
rubber-modified polyepoxide resins such as the product prepared from a
polyglycidyl
ether of bisphenol A and an acid-functional polybutadiene.
Other suitable examples of flexible polyepoxides for use according to the
present
invention include an epoxy-functional adduct which is prepared from a flexible
acid-
functional polyester and polyepoxide.
The acid-functional polyester generally has an acid value of at least 10 mg
KOH/g,
generally from about 140 to about 350 mg KOH/g and suitably from about 180 to
about
260 mg KOH/g, as determined by ASTM 974-87.
Linear polyesters are more suitable than branched polyesters for use herein.
Acid-
functional polyesters can be prepared by the polyesterification of an organic
polycarboxylic acid or anhydride thereof with an organic polyol. Usually, the
polycarboxylic acids and polyols are aliphatic or aromatic dibasic acids and
diols.
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The diols which are usually employed in making the polyester include alkylene
glycols,
such as ethylene glycol, diethylene glycol, neopentyl glycol and other diols
such as
hydrogenated bisphenol A, cyclohexanediol, cyclohexanedimethanol,
caprolactonediol,
for example, the reaction product of epsilon-caprolactone and ethylene glycol,
hydroxy-
alkylated bisphenols, polyether glycols, for example, poly(oxytetramethylene)
glycol,
poly(oxyethylene) glycol, poly(oxypropylene) glycol and the like. Polyols of
higher
functionality can also be used although diols are more suitable. Examples
include
trimethylolpropane, trimethylolethane, pentaerythritol, glycerol, isosorbide,
tetramethyl
cyclobutane diol and the like, as well as higher molecular weight polyols such
as those
produced by oxyalkylating lower molecular weight polyols.
The acid component of the polyester comprises monomeric dicarboxylic acids or
anhydrides having 2 to 36 carbon atoms per molecule. Among the acids which are
useful
are phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic
acid,
hexahydrophthalic acid, adipic acid, azelaic acid, sebacic acid, maleic acid,
glutaric acid,
chlorendic acid, tetrachlorophthalic acid, tetrabromomphthalic acid,
decanedioic acid,
dodecanedioic acid, rosin acids, diphenolic acid, gallic acid, and other
dicarboxylic acids
of varying types, for example, Diels-Alder adducts of unsaturated C18 fatty
acids.
The polyester may include minor amounts of monobasic acids such as benzoic
acid,
stearic acid, acetic acid, hydroxystearic acid and oleic acid. Also, there may
be employed
higher polycarboxylic acids such as trimellitic acid. Where acids are referred
to above, it is
understood that anhydrides of those acids which form anhydrides can be used in
place of
the acid. Also, lower alkyl esters of the acids such as dimethyl glutarate and
dimethyl
terephthalate can be used.
According to the present invention, the polyester used to make the epoxy-
functional
adduct may be prepared from a polycarboxylic acid component comprising a
polycarboxylic acid or mixture of acids having from 7 to 16 carbon atoms and a
polyol
component comprising a portion of diethylene glycol.
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The polyepoxides that are used to prepare the epoxy-functional adduct of
flexible acid-
functional polyester and polyepoxide can be selected from those as defined
above for the
polyepoxide-functional component according to the present invention.
Other suitable polyepoxy-functional compounds are epoxy functional acrylic
resins. Such
resins can be prepared by free-radical addition polymerization of
(meth)acrylic monomers,
optionally in combination with vinyl monomers or other monomers comprising at
least
one carbon-carbon double bond, wherein the monomer composition comprises at
least one
epoxy functional compound having a one carbon-carbon double bond.
Suitable epoxy-functional ethylenically unsaturated monomers may be selected
from
glycidyl (meth)acrylate, allyl glycidylether, vinyl glycidylether, vinyl
cyclohexene oxide,
limonene oxide, 2-ethylglycidylacrylate, 2-ethylglycidylmethacrylate, 2-(n-
propyl)glycidylacrylate, 2-(n-propyl)glycidylmethacrylate, 2-(n-
butyl)glycidylacrylate, 2-
(n-butyl)glycidylmethacrylate, glycidylmethylmethacrylate, glycidylacrylate,
(3',4'-
epoxyhepty1)-2-ethylacrylate, (3',4'-epoxyhepty1)-2-ethylmethacrylate, (6',7'-
epoxyheptyl)acrylate, (6',7'-epoxyheptyl)methacrylate, ally1-3,4-epoxyheptyl
ether, 6,7-
epoxyheptylallylether, vinyl-3,4-epoxyheptylether, 3,4-epoxyheptylvinyl ether,
6,7-
epoxyheptylvinylether, o-vinylbenzylglycidyl ether, m-
vinylbenzylglycidylether, p-
vinylbenzylglycidylether, 3-vinyl cyclohexene oxide, alpha-methyl glycidyl
methacrylate,
3,4-epoxycyclohexylmethyl (meth)acrylate and combinations thereof. Glycidyl
(meth)acrylate is particularly suitable.
Suitable additional monomers for the preparation of the epoxy-functional
acrylic resin can
be selected from
- ethylenically unsaturated nitrile compounds;
- vinyl aromatic monomers;
- alkyl esters of ethylenically unsaturated acids;
- hydroxyalkyl esters of ethylenically unsaturated acids;
- amides of ethylenically unsaturated acids;
- ethylenically unsaturated acids;
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- ethylenically unsaturated sulfonic acid monomers and/or ethylenically
unsaturated
phosphorous-containing acid monomers
- vinyl carboxylates;
- conjugated dienes;
- monomers having at least two ethylenically unsaturated groups; and
- combinations thereof.
Examples of ethylenically unsaturated nitrile monomers which can be used for
the
preparation of the epoxy-functional acrylic resin include polymerizable
unsaturated
aliphatic nitrile monomers which contain from 2 to 4 carbon atoms in a linear
or branched
arrangement, which may be substituted either by acetyl or additional nitrile
groups. Such
nitrile monomers include acrylonitrile, methacrylonitrile, alpha-cyanoethyl
acrylonitrile,
fumaronitrile and combinations thereof, with acrylonitrile being particularly
suitable.
Representatives of vinyl-aromatic monomers include, for example, styrene, a-
methylstyrene, p-methylstyrene, t-butylstyrene and vinyltoluene. Suitably, the
vinyl-
aromatic monomers are selected from styrene, alpha-methyl styrene and
combinations
thereof.
Esters of (meth)acrylic acid that can be used for the preparation of the epoxy-
functional
acrylic resin include n-alkyl esters, iso-alkyl esters or tert-alkyl esters of
acrylic or
(meth)acrylic acid in which the alkyl group has from 1 to 20 carbon atoms, the
reaction
product of methacrylic acid with glycidyl ester of a neoacid such as versatic
acid,
neodecanoic acid or pivalic acid and hydroxyalkyl (meth)acrylate and
alkoxyalkyl
(meth)acrylate monomers.
In general, suitable alkyl esters of (meth)acrylic acids may be selected from
Ci-C20 alkyl
(meth)acrylate, suitably Cl-C10-alkyl (meth)acrylates. Examples of such
acrylate
monomers include n-butyl acrylate, secondary butyl acrylate, methyl acrylate,
ethyl
acrylate, hexyl acrylate, tert-butyl acrylate, 2-ethyl-hexyl acrylate,
isooctyl acrylate, 4-
methy1-2-pentyl acrylate, 2-methylbutyl acrylate, methyl methacrylate, butyl
methacrylate,
n-butyl methacrylate, isobutyl methacrylate, ethyl methacrylate, isopropyl
methacrylate,
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hexyl methacrylate, cyclohexyl methacrylate and cetyl methacrylate. It is
particularly
suitable to select the esters of (meth)acrylic acids from methyl
(meth)acrylate, ethyl
(meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl
(meth)acrylate
and combinations thereof.
The hydroxy alkyl(meth)acrylate monomers which can be used for the preparation
of the
epoxy-functional acrylic resin include hydroxyalkyl acrylate and methacrylate
monomers
which are based on ethylene oxide, propylene oxide and higher alkylene oxides
or
mixtures thereof Examples are hydroxyethyl acrylate, hydroxypropyl acrylate,
hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxybutyl
acrylate.
Suitably, the hydroxy alkyl(meth)acrylate monomer is selected from 2-hydroxy
ethyl
(meth)acrylate.
Amides of ethylenically unsaturated acids that can be used for the preparation
of the
epoxy-functional acrylic resin include acrylamide, methacrylamide, and
diacetone
acrylamide. A particularly suitable amide monomer is (meth)acrylamide.
Vinyl ester monomers which can be used to prepare the epoxy-functional acrylic
resin
include vinyl acetate, vinyl proprionate, vinyl butyrate, vinyl benzoate,
viny1-2-
ethylhexanoate, vinyl stearate, and the vinyl esters of versatic acid. The
particularly
suitable vinyl ester is vinyl acetate.
The ethylenically unsaturated carboxylic acid monomers suitable for the
preparation of the
epoxy-functional acrylic resin include monocarboxylic acid and dicarboxylic
acid
monomers and monoesters of dicarboxylic acid. Carrying out the present
invention, it is
particularly suitable to use ethylenically unsaturated aliphatic mono- or
dicarboxylic acids
or anhydrides which contain from 3 to 5 carbon atoms. Examples of
monocarboxylic acid
monomers include acrylic acid, methacrylic acid, crotonic acid and examples of
dicarboxylic acid monomers include fumaric acid, itaconic acid, maleic acid
and maleic
anhydride. Examples of other suitable ethylenically unsaturated acids include
vinyl acetic
acid, vinyl lactic acid, vinyl sulfonic acid, 2-methy1-2-propene-1-sulfonic
acid, styrene
sulfonic acid, acrylamidomethyl propane sulfonic acid and the salts thereof.
Suitably, the
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ethylenically unsaturated carboxylic acid monomers are selected from
(meth)acrylic acid,
crotonic acid, itaconic acid, maleic acid, fumaric acid and combinations
thereof.
Conjugated diene monomers suitable for the preparation of the epoxy-functional
acrylic
resin include conjugated diene monomers, selected from 1,3-butadiene,
isoprene, 2,3-
dimethy1-1,3-butadiene, 2,3-dimethy1-1,3-butadiene, 2-chloro-1,3-butadiene,
1,3-
pentadiene, 1,3-hexadiene, 2,4-hexadiene , 1,3-octadiene, 2-methyl-1,3-
pentadiene, 2,3-
dimethy1-1,3-pentadiene, 3,4-dimethy1-1,3-hexadiene, 2,3-diethy1-1,3-
butadiene, 4,5-
diethy1-1,3-octadiene, 3-buty1-1,3-octadiene, 3,7-dimethy1-1,3,6-octatriene, 2-
methyl-6-
methylene-1,7-octadiene, 7- methyl-3-methylene-1,6-octadiene, 1,3,7-
octatriene, 2-ethyl-
1, 3-butadiene, 2-amyl-1,3-butadiene, 3, 7-dimethy1-1,3,7-octatriene, 3,7-
dimethy1-1,3,6-
octatriene, 3,7,11-trimethy1-1,3,6,10-dodecatetraene, 7,11-dimethy1-3-
methylene-1,6,10-
dodecatriene, 2,6-dimethy1-2,4,6-octatriene, 2-phenyl-1,3-butadiene and 2-
methy1-3-
isopropy1-1,3-butadiene and 1,3-cyclohexadiene. 1,3-Butadiene, isoprene and
combinations thereof are particularly suitable conjugated dienes.
It is also possible to use a combination of two or more, such as three or more
or four or
more, different polyepoxy-functional compounds in resin component (al) that
may be
selected from those as disclosed above.
Suitable polyepoxy-functional compounds according to the present invention may
be
selected from diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol
F, resorcinol
diglycidyl ether, epoxy phenol novolac resin, epoxy cresol novolac resins,
epoxy
functional (poly)siloxanes, epoxy functional polysilfides, epoxy-functional
adducts of
acid-functional polyesters and polyepoxides, for example, those that are
described above.
The beta-hydroxy ester of (meth)acrylic acid (a2) optionally present in the
resin
component (a) of the intumescent coating compositions of the present invention
may
comprise a plurality of beta-hydroxy ester of (meth)acrylic ester groups
resulting from the
.. reaction of a polyepoxide with (meth)acrylic acid. The polyepoxide can be
reacted with
the (meth)acrylic acid in an epoxy-carboxylic acid equivalent ratio of 1:0.1
to 1:1.2,
suitably 1:0.5 to 1:1.2 more suitably 1:1 to 1:1.05.
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The polyepoxides that can be used for the reaction product of polyepoxide with
(meth)acrylic acid can be selected from those polyepoxides as disclosed above
with
respect to component (al) of the intumescent coating composition of the
present
invention. Particularly suitable epoxides that can be used for making the beta-
hydroxy
ester of (meth)acrylic acid (component (a2) of the intumescent coating
composition
according to the present invention are selected from diglycidyl ether of
bisphenol A,
diglycidyl ether of bisphenol F, epoxy phenyl novolac resins, epoxy cresol
novolac resins,
epoxy-functional acrylic resins, epoxy-functional polyester or combinations
thereof
A particularly suitable beta-hydroxy ester of (meth)acrylic acid is the
reaction product of
EPIKOTE 828 (reaction product of bisphenol A with epichlorohydrin) with
acrylic acid,
commercially available from Allnex as EBECRYL 3720).
In addition, or alternatively to the beta-hydroxy ester of (meth)acrylic acid
(a2), a
(meth)acrylate-functional compound (a3) different from compound (a2) may be
present in
resin component (a). Thereby, the viscosity of the intumescent coating
composition of the
present invention can be suitably adjusted. Thus, it is believed that the
optional component
(a3) functions as a reactive diluent in the intumescent coating composition of
the present
invention. The optional (meth)acrylate-functional component (ii) of the
intumescent
coating composition of the present invention may be selected from
poly(meth)acrylates of
1,4-butanediol, neopentyl glycol, ethylene glycol, 1,2-propanediol, 1,3-
propanediol, 2,2,4-
trimethy1-1,3-pentanediol, 1,6-hexanediol, 1,4-cyclohexane dimethanol, para-
xylene
glycol, 1,4-cyclohexane diol, trimethylolethane, trimethylolpropane,
pentaerythritol,
polyether glycols, for example, poly(oxytetramethylene) glycol,
poly(oxyethylene) glycol,
poly(oxypropylene) glycol and combinations thereof
The present inventors found out that the addition of the beta-hydroxy ester of
(meth)acrylic acid (a2) and/or the (meth)acrylate-functional compound (a3)
different
therefrom results in a considerable increase of curing rate of the coating
composition.
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Without wanting to be bound by theory, it is believed that this increase in
curing rate is
due to the Michael addition reaction between the acrylic group of the beta-
hydroxy ester
of (meth)acrylic acid (i) or the (meth)acrylate-functional compound (ii)
different
therefrom and the polyamine and/or the polythiol-functional compound.
In the intumescent coating composition of the present invention the polyepoxy-
functional
compound (al) may be present in an amount of 20 to 95 wt.-%, suitably 40 to 95
wt.-%,
and the beta-hydroxy ester of (meth)acrylic acid (a2) may be present in an
amount of 5 to
80 wt.-%, suitably 5 to 60 wt.-%, whereby the weight percentage is based on
the total
weight of polyepoxy-functional compound (al) and beta-hydroxy ester(s) of
(meth)acrylic
acid (a2).
Furthermore, in the intumescent coating composition of the present invention,
the
polyepoxy-functional compound (al) may be present in an amount of 25 to 95 wt.-
%,
suitably 40 to 95 wt.-%, the beta-hydroxy ester of (meth)acrylic acid (a2) may
be present
in an amount of 5 to 75 wt.-%, suitably 5 to 60 wt.-%, and the (meth)acrylate-
functional
compound (a3), different from compound (a2), may be present in an amount 0 to
50 wt.-
%, suitably 5 to 30 wt.-%, wherein the weight percentages are based on the
total weight of
compounds (al), (a2) and (a3).
In the intumescent coating composition of the present invention, the amount of
the resin
component (a) may be 10-40 wt.-%, based on the total solid weight of the
intumescent
coating composition, such as 15-38 wt.-%, 22-36 wt.-%, or 23-30 wt.-%.
Alternatively,
the amount of the polymer in the coating composition of the present invention
may be 10,
11, 12, 13, 14, 15, 16, 17, 18, 19 wt.-% to 30, 31, 32, 33, 34, 35, 36, 37,
38, 39, 40 wt.-%.
The endpoints of the above ranges can be arbitrarily combined to define the
amount of the
polymer in the intumescent coating composition of the present invention.
Crosslinker component (b)
There is no particular limit to the crosslinker component (b) used in the
curable
intumescent coating composition according to the present invention, as long as
it contains
at least one compound (bl) bearing a plurality of functional groups that are
reactive with
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the epoxy groups of the polyepoxy-functional compound (al). Curing can take
place either
at ambient temperature or upon application of heat, wherein curing at ambient
temperature
is particularly suitable for the intumescent coating composition according to
the present
invention.
Suitable compounds (bl) may be selected from
- a polyamine-functional compound suitably selected from an aliphatic
polyamine,
an aromatic polyamine, poly(amine-amides), and combinations thereof: or
- a polythiol-functional compound suitably selected from polysulfide
thiols,
polyether thiols, polyester thiols, pentaerythritol based thiols; or
- combinations thereof.
The polyamine curing agent can be selected from aliphatic polyamines, aromatic
polyamines, polyamine amides, polyetheramines, for example those commercially
available from Huntsman Cooperation, The Woodlands, Texas, polysiloxane
amines,
polysulfide amines or combinations thereof Examples include diethylene
triamine, 3,3-
amino-bis-propylamine, triethylene tetraamine, tetraethylene pentamine, m-
xylylenediamine, isophorone diamine, 1,3-bis(aminoethyl)cyclohexane, bis(4-
aminocyclohexyl)methane, N-aminoethyl piperazine, 4,4'-diaminodiphenyl
methane, 4,4'-
diamino-3,3'-diethyl diphenyl methane and diamino diphenylsulphone and the
reaction
product of a polyamine and an aliphatic fatty acid such as the series of
materials sold by
BASF under the trademark VERSAMID can be used, the latter being particularly
suitable.
In addition, adducts of any above polyamines can also be used. The adduct of
polyamine
is formed by reacting polyamine with a suitable reactive compound, such as an
epoxy
resin. This reaction will decrease the content of free amine in the curing
agent, making it
more useful at low temperature and/or high humidity environment.
As a curing agent, various polyetheramines, such as various Jeffamines
available from
Huntsman Corp., including, but not limited to, Jeffamine D-230, Jeffamine D-
400,
Jeffamine 600, Jeffamine 1000, Jeffamine 2005 and Jeffamine 2070, etc, can
also be used.
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As a curing agent, various polyamides can also be used. Generally, polyamides
contain
reaction products of dimer fatty acid and polyethyleneamine, and small amounts
of
monomer fatty acid. Dimer fatty acid is prepared by the oligomerization of
monomer fatty
acid. Polyethyleneamine can be any higher polyethyleneamine, such as
diethylenetriamine, triethylenetetraamine, tetraethylenepentaamine, etc.,
wherein the most
commonly used is diethylenetriamine. When polyamides are used as the curing
agent, it
can make the coating have a good balance between corrosion resistance and
waterproof
property. Further, polyamides can also make the coating have good flexibility,
proper
curing rate and other advantageous factors.
1()
The polythiol compounds may be selected from polysulfide thiols, polyether
thiols,
polyester thiols, pentaerythritol based thiols; or combinations thereof A
particularly
suitable polythiol compound is ThioplastO G4, commercially available from Akzo
Nobel
Functional Chemicals GmbH&Co KG, Greiz, Germany.
In the intumescent coating composition of the present invention, the
equivalent ratio of the
combined functional groups such as epoxy groups and (meth)acrylate groups in
component (a) to the functional groups in compound (bl) may be from 2:1 to
1:2, suitably
from 1.05:1.0 to 1:2, particularly suitable from 1:1.4 to 1:2.
In the intumescent coating composition of the present invention, the amount of
compound
(1)1) is typically 10-30 wt.-%, based on the total solids weight of the
intumescent coating
composition, such as 15-20 wt.-%, 16-19 wt.-%, or 17-19 wt.-%. Alternatively,
the
amount of the compound (b1)in the coating composition of the present invention
may be
10, 11, 12, 13, 14 or 15 wt.-% to 18, 19, 20, 21, 22, 23, 24 or 25 wt.-%. The
endpoints of
the above ranges can be arbitrarily combined to define the amounts of various
curing
agents in the intumescent coating composition of the present invention.
The intumescent coating composition of the present invention can also comprise
a curing
promoter. A curing promoter is a kind of material which can accelerate the
curing of the
resins, lower the curing temperature, shorten the curing time. Typical curing
promoters
include aliphatic amine promoters, such as triethanolamine,
triethylenediamine, etc.;
anhydride promoters, such as BDMA, DBU, etc.; polyetheramine catalysts; tin
promoters,
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such as dibutyltin dilaurate, stannous octoate, etc. In one embodiment of the
present
invention, the curing promoter is ANCAMINE K54, which is commercially
available
from Air Products.
Suitable amounts of curing promoters are 0.1 to 5 wt.-%, more suitably 1 to 3
wt.-% based
on the total solids weight of the intumescent coating composition.
The crosslinker component (b) of the intumescent coating composition of the
present
invention may further comprise a compound (b2) than can undergo condensation
reactions
optionally in presence of moisture with the Si-X functionality of the organo
silane
compound (c) of the intumescent coating composition of the present invention.
Suitable
compounds (b2) may be selected from silanes of formula (III) or (IV),
RkSiX1 (III)
RmX3_rnSiR' SiRnX3-n (IV)
wherein R' is defined as an alkyl group of 1 to 20 carbon atoms, more suitably
1 to 4
carbon atoms, R and X are defined as for the organo silane compound (c) of the
intumescent coating composition according to the present invention including
the
particularly suitable embodiments for (c) as will be discussed below, and
k is an integer of 0 to 2,1 is an integer of 2 to 4 and the sum of k +1 is 4.
m and n are integers of 0-2, m+n is below or equal to 3.
Particularly suitable compounds (b2) may be selected from tetraalkoxy silanes,
hydrocarbyl trialkoxy silanes and dihydrocarbyl dialkoxy silanes, wherein the
hydrocarbyl
groups may be suitable selected from Ci-C4 alkyl and phenyl und the alkoxy
groups may
be suitably selected from Cl-C4 alkoxy.
The compound (b2) may be present in an amount 0 to 5 wt.-% suitably 0.1 to 4
wt.-%,
more suitably 0.5 to 4 wt.-%, even more suitably 0.5 to 3 wt.-% based on the
total solids
weight of the intumescent coating composition. It is particularly suitable if
compound (b2)
is absent.
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Organo silane compound (c):
Organo silane compounds (c) useful in the intumescent coating composition
according to
the present invention are defined above. Suitable organo silane compound (c)
present in
the intumescent coating composition of the present invention may be selected
from organo
silane compounds of the formula (I) or (II), wherein
- L is selected from alkylene and cycloalkylene groups having 1 to 10
carbon atoms,
suitably 2 to 6 carbon atoms and a bond if Y is a vinyl group; and/or
- K is selected from alkylene and cycloalkylene groups having 1 to 10
carbon atoms,
suitably 2 to 6 carbon atoms and a bond; and/or
- Y is selected from an epoxy containing group, an amino group, a polyamino
group,
an amido group, a thiol group, a carboxylic acid group, a hydroxy group, a
(meth)acryloxy group and a vinyl group; and/or
- X is selected from alkoxy groups having suitably 1 to 4 carbon atoms,
chloro,
acyloxy and oximino groups, suitably from alkoxy groups having 1 to 4 carbon
atoms; and/or
- R is a Ci to C4 alkyl group; and/or
- B is a polyvalent alkyl group; and/or
- n is 1, o is 0 and m is 3; and/or
- u is 1 and z is 2.
Suitable organo silane compounds may selected from vinyl trialkoxysilane, 3-
glycidoxypropyl trialkoxysilane, 3-(meth)acryloxypropyl trialkoxysilane,
aminoalkyl
trialkoxysilane, aminoalkyl di alkyl monoalkoxysilane, bis- (aminoalkyl)
dialkoxysilane,
thiolalkyl trialkoxysilane, thiolalkyl alkyl dialkoxysilane, thiolalkyl di
alkyl
monoalkoxysilane and combinations thereof Other suitable organo silane
compounds are
compounds according to formula (II) wherein z is 2, known to the person
skilled in the art
as dipodal silanes, which are also commercially available. Particularly
suitable silane
compounds (c) may be selected from vinyl trimethoxysilane, vinyl
triethoxysilane,
vinyl triacetoxy silane, vinyltris(2-butylidenaminooxy)silane, 3-
glycidoxypropyl
trimethoxysilane, 3-glycidoxypropyl triethoxy silane, 3-(meth)acryloxypropyl
trimethoxysilane, 3-(meth)acryloxypropyl triethoxysilane, 3-aminopropyl
trimethoxysilane, 3-aminopropyl triethoxysilane, 3-aminopropyl dimethyl
methoxysilane,
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bis-(3-aminopropyl) dimethoxysilane, thiolethyl trimethoxysilane, N-[3-
(trimethoxysilyl)propyl] ethylenediamine, N43-
(trimethoxysilyppropyl]diethylenetriamine, f3-(3,4-epoxycyclohexypethyl
trimethoxysilane, bis[3-(trimethoxysilyl)propyl]amine,.
The coating composition of any of the preceding aspects, wherein the amount of
the
organo silane compound (c) is 5 to 18 wt.-%, suitably 10 to 18 wt.-% based on
the total
weight of the intumescent coating composition. Suitable lower limits for the
range of the
amount of the organo silane compound (c) may be at least 5, at least 5,5, at
least 6, at least
6.5, at least 7, at least 7.5, at least 8, at least 8.5, at least 9,5, at
least 10, at least 10.5, at
least 11, at least 11.5, at least 12, at least 12.5, at least 13, at least
13.5, at least 14, at least
14.5, at least 15 wt.-% based on the total weight of the intumescent coating
composition.
Suitable upper limits for the range of the amount of the organo silane
compound (c) may
be at most 20, at most 19,5, at most 19, at most 18.5, at most 18, at most
17.5, at most 17,
at most 16.5, at most 16, at most 15.5, at most 15, at most 14.5, at most 14,
at most 13.5,
at most 13, at most 12.5, at most 12, at most 11.5, at most 11, at most 10.5,
at most 10 wt.-
% based on the total weight of the intumescent coating composition. The person
skilled in
the art will appreciate that any range defined by any one of the above lower
limits and any
one of the above upper limits is disclosed herein.
The intumescent coating composition of the present invention further
comprises, as
component (d), a compound providing an expansion gas upon thermal
decomposition.
The expansion gas serves to cause the fire-protective intumescent composition
to foam
and swell when exposed to high temperature of flames. As a result of this
expansion, the
char which is formed is a thick, multicelled material which serves to insulate
and protect
the underlying substrate. The source of expansion gas that may be used in the
intumescent
coating composition of the present invention is a nitrogen-containing
material. Examples
of suitable nitrogen-containing materials include melamine, salts of
phosphoric acid,
guanidine, methylolated melamine, hexamethoxymethyl melamine, urea,
dimethylurea,
melamine pyrophosphate, dicyandiamide, guanylurea phosphate and glycine.
Suitably,
melamine is used. Other conventional sources of expansion gas can also be used
such as
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those materials which liberate carbon dioxide. Examples are alkaline earth
metals such as
calcium carbonate or magnesium carbonate. Compounds which release water vapor
as
they decompose upon heating, for example calcium hydroxide, magnesium
dihydroxide or
aluminum trihydroxide, may also be used. Other examples of such compounds are
boric
acid and boric acid derivatives such as boric acid esters and metal borates.
A suitable amount of component (d) in the intumescent coating composition of
the present
invention may range from 0.1 to 25 wt.-%, suitably 1 to 10 wt.-%, whereby the
weight
percentage is based on the total solids weight of the composition.
The intumescent coating composition of the present invention may comprise
optional
additives (f) that are selected from a phosphorous source, a boron source, a
zinc source, an
acid source, a metal oxide, for example pre-hydrolysed
tetraethylorthosilicate, aluminum
oxide, titanium isopropoxide, a carbon source, inorganic fillers, mineral
fibers, for
.. example CHOP VANTAGE from PPG, Coatforce or Roxul fibers from Lapinus,
rheology
additives, organic solvents, pigments, foam stabilizers, and combinations
thereof
The optional source of phosphorous can be selected from a variety of
materials, such as,
for example, phosphoric acid, mono- and diammonium phosphate, tris-(2-
chloroethyl)phosphate, phosphorus-containing amides such as phosphorylamide,
and
melamine pyrophosphate. Suitably, the source of phosphorous is an ammonium
polyphosphate represented by the formula (NH4)n+2 Pn 03n+1, wherein n is an
integer of at
least 2, suitably n is an integer of at least 50. The intumescent coating
composition of the
present invention may contain an amount of phosphorous in the range of 0.05 to
30 wt.-%,
suitably 0.5 to 10 wt.-%, based on the total solid weight of the coating
composition. The
phosphorous is believed to function as a char promoter in the intumescent
composition.
The optional source of zinc can be selected from a variety of materials. It is
believed that
the zinc material contributes to the formation of a small-celled structure in
the char. The
small cells of the char afford better insulation of the substrate and are
better able to retain
the char's integrity and adhere to the substrate even in the absence of
external reinforcing
materials. Thus, cracking of the char and its breaking away from the substrate
are
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minimized and a greater measure of protection is afforded to the underlying
steel.
Examples of suitable materials which are sources of zinc include zinc oxide,
zinc salts,
such as zinc borate and zinc phosphate, zinc carbonate; also zinc metal can be
used.
Suitably, zinc borate is utilized. The intumescent coating composition of the
present
invention may contain an amount of zinc in the range from 0.1 to 25 wt.-%,
suitably 0.5 to
12 wt.-%, based on the total solids weight of the composition.
The source of boron may be selected from ammonium pentaborate or zinc borate,
boron
oxide, borates such as sodium borate, potassium borate and ammonium borate,
borate
esters such as butyl borates or phenyl borates and combinations thereof The
intumescent
coating composition of the present invention may contain an amount of boron in
the range
from 0.1 to 10 wt.-%, suitably 1 to 6 wt.-%, whereby the weight percentage is
based on
the total solids weight of the composition.
The acid source may be selected from ammonium phosphate, ammonium
polyphosphate,
diammonium diphosphate, diammonium pentaborate, phosphoric acid-generating
materials, boric acid, metal or organic borates and combinations thereof The
total amount
of acid source, if present, may be 5 to 30 wt.-%, based on the total solids
weight of the
coating composition.
The intumescent coating composition of the present invention further comprises
a carbon
source. The carbon source transforms into char upon exposure to fire or heat,
thereby
forming an anti-fire protective layer on the substrate. According to the
present invention,
carbon sources can be, for example, aromatic compounds and/or tall oil fatty
acids
(TOFA) and/or polyhydroxy compounds such as pentaerythritol,
dipentaerythritol,
glycerol, oligomeric glycerol, xylitol, mannitol, sorbitol and polymers such
as polyamides,
polycarbonates, polyurethanes, and combinations thereof The inventors of the
present
invention have surprisingly found that when carbon sources including aromatic
compounds and/or tall oil fatty acids are used as the carbon source in
intumescent coating
composition of the present invention, the resultant intumescent coating will
not only have
comparable or even better anti-fire properties than the similar type of
intumescent coatings
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but can also maintain these required properties after undergone low
temperatures. It will
also be appreciated that the polymer may also be a carbon source.
In the intumescent coating composition of the present invention, the amount of
the carbon source
can be up to 18 wt.-%, based on the total weight of the intumescent coating
composition, such as
5-18 wt.-%, 11-17 wt.-%, or 12-16 wt.-%. Alternatively, the amount of the
carbon source in the
coating composition of the present invention can be 5, 6, 7, 8, 9, 10, 11, 12,
13 wt.-% to 15, 16, 17,
18 wt.-%. The endpoints of the above ranges can be arbitrarily combined to
define the amounts of
various carbon sources in the intumescent coating composition of the present
invention.
It should be understood that the phosphorus, zinc, boron and expansion gas can
each be
provided by a separate source material or, alternatively, a single material
may be a source
of more than one of the aforelisted additional components. For example,
melamine
pyrophosphate can provide a source of both phosphorus and expansion gas.
The optional reinforcing fillers (e) may be chosen from among a large array of
conventionally utilized materials, including fibrous reinforcements and
platelet
reinforcements, which are suitable over other fillers. Examples of fibrous
reinforcements
include glass fibers, ceramic fibers, e.g., aluminum oxide/silicon oxide, and
graphite
fibers. Platelet reinforcements include hammer-mill glass flakes, mica, and
wollastonite.
Other suitable fillers include metal oxides, titanium oxides, clay, talc,
silica, diatomaceous
earth, lapinus fibers and various pigments. The reinforcing filler is
believed to assist in
controlling expansion of the fire-protective composition prior to and during
char formation
so that the resultant char is hard and uniform.
One advantage of the present invention is, that the intumescent coating
composition is
tintable without compromising the fire protection and mechanical properties of
the cured
intumescent coating. In particular the reinforcing fillers for example white
reinforcing
fillers do not have to be present in order to provide a hard and uniform char.
Thus, in the
intumescent coating composition the amount of white pigments and/or fillers
selected
from aluminum oxides, silicon oxide, mica, wollastonite, titanium oxides,
clay, talc, and
diatomaceous earth compounds may be less than 2 wt.-%, suitably between 0-0.1
wt.-%
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based on the total weight of the composition, and the amount of colored
pigments,
particularly black pigments may be at least 0.5 wt.-%, suitably between 1-5
wt.-% based
on the total weight of the composition.
The intumescent coating composition of the present invention may also contain
a variety
of conventional additives, such as rheology additives, organic solvents, foam
stabilizers,
pigments, flame spread control agents, and the like. These ingredients are
optional and can
be added in varying amounts. In particular the intumescent coating composition
according
to the present invention is liquid at 23 C and atmospheric pressure (i.e.
lbar) and is
.. substantially non-aqueous i.e. contains less than 5 wt.-%, suitably less
than 3 wt.-%, more
suitable less than 1 wt.-% based on the total weight of the intumescent
coating
composition or even no intentionally added water.
As mentioned above the crosslinked intumescent coating expands at a
temperature above
the activation temperature to induce thermal decomposition of compound (c) and
optionally is charred. Upon the action of heat and fire, the expanded foam
starts to char,
wherein the resin material and optionally present additional carbon sources
form a porous
carbon network that exhibits stability at high temperatures and provides for
thermal
insulation in order to prevent or at least inhibit for a prolonged period of
time a thermal
runaway of the battery or individual battery cells.
The intumescent coating composition may be configured as two-package system,
wherein
component (a) is comprised in a first package (A) ;
component (b) is comprised in a second package (B);
compound (c) is comprised in a third package (C) or if Y- is a functional
group reactive
with the compounds in component (a) compound (c) is present in the second
package (B)
or if Y- is a functional group reactive with the compounds in component (b)
compound (c)
is present in the first package (A)
the compound providing an expansion gas upon thermal decomposition (d) and any
of the
additives (e) and (f) if present are comprised in any combination in either
package (A), (B)
or (C) or in any combination of these packages or are comprised in one or more
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packages (D); wherein the packages are mixed immediately prior to application
of the
coating composition.
It is particularly suitable that the composition be solvent-free and spray-
applied. If desired,
thinning can be accomplished with a variety of conventional solvents such as,
xylene,
methylene chloride or 1,1,1-trichloroethane.
The intumescent coating composition of the present invention may be applied to
provide
the various dry coating thicknesses as desired. Suitable dry coating
thicknesses can range
1() from 10 -20,000 microns, such as 50 ¨ 5000 microns, such as 100 ¨ 2000
microns.
In a method for coating a substrate the intumescent coating composition of the
present
invention is at least partial applied to a substrate and subsequently
optionally cured.
Suitable substrate may be selected from a metal substrate, suitably selected
from
aluminum and steel substrates or plastic substrate suitably selected from
polycarbonate.
In particular, the intumescent coating composition of the present invention
can be applied
to a structural element of a battery, in particular lithium ion battery. The
battery may
comprise exterior wall elements defining a housing and optionally interior
wall elements,
wherein the intumescent coating composition is at least partially applied to
the external
and/or internal side of any of the exterior wall elements and/or to any side
of any of the
interior wall elements, if present. The exterior wall and/or interior wall
elements may
comprise a material selected from any of composite, steel, aluminum and
polycarbonate.
The battery, in particular lithium ion battery, may be a battery pack
comprising a plurality
of individual battery cells, wherein the crosslinked intumescent coating is
positioned to
thermally insulate at least some of the individual battery cells from each
other in the
expanded and optionally charred state. In addition, the intumescent coating
composition
may be applied to the housing walls and interior dividing walls of the battery
pack as
discussed above.
In order to provide fire protection for articles comprising a battery and
their users it is also
within the ambit of the present invention to apply the intumescent coating
composition to
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a part of an article adjacent to the battery between the battery and the
article to insulate the
article from the battery. In such cases a conventional battery or a battery
according to the
present invention can be employed. The article may be, for example, a mobile
phone, a
tablet or a laptop computer.
Alternatively, the article may be a vehicle such as a hybrid or electric car,
bus or truck. In
such vehicles it is common to position the battery, especially the lithium ion
battery, due
to its weight as a flat battery pack underneath the floor portion of the
vehicle body, for
example the car body. In such cases, the intumescent coating of the present
invention may
be applied to the floor portion of the vehicle adjacent to the battery between
battery and
the vehicle body. Thereby, in an event of a thermal runaway of the battery or
a battery fire,
the car body, especially the passenger cabin, is protected by the crosslinked
intumescent
coating so that the fire will not spread into the passenger cabin and the heat-
up of the
passenger cabin will be limited for a prolonged period of time so that the
passengers will
have sufficient time to safely escape from the vehicle in case of such an
incident.
The present invention is defined by the following aspects:
1. An intumescent coating composition comprising:
(a) a resin component comprising
- (al) a polyepoxy-functional compound and
optionally;
- (a2) a beta-hydroxy ester of (meth)acrylic acid; and/or
- (a3) a (meth)acrylate-functional compound different from
compound (a2);
(b) a crosslinker component comprising at least one compound (1)1) bearing
a
plurality of functional groups that are reactive with the epoxy groups of the
polyepoxy-functional compound;
(c) 5 to 20 wt.-% based on the total weight of the intumescent coating
composition of an organo silane compound selected from organo silane
compounds of formula (I) or (II) and combinations thereof
(I),
(Y - L)õ ¨ B ¨ (K - (II)
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wherein:
- n and m are integers from 1 to 3 and o is an integer from
0 to 2, wherein n + m + o is 4;
- y is an integer from 1 to 3 and w is an integer from 0 to 2, wherein y
+ w is 3;
- u is an integer of at least 1 and z is an integer of at least 2;
- B is a polyvalent organic group, wherein the valency of B is
u + z;
- L is a divalent organic group or a bond if Y is a vinyl group;
K is a divalent organic group or a bond.
- Y comprises a functional group reactive with the epoxy groups
and/or the (meth)acrylate groups if present of component (a) or the
functional groups of component (b);
- X is independently selected at each occurrence from chloro, alkoxy,
acyloxy and oximino; and
- R is a hydrocarbyl group;
(d) a compound providing an expansion gas upon thermal
decomposition;
wherein
the compounds as defined for (a) to (d) differ from each other, wherein
the intumescent coating composition is liquid at 23 C and atmospheric pressure
and comprises less than 5 wt.-% based on the total weight of the composition
of
water.
2. The coating composition of aspect 1, wherein
for the organo silane compound of the formula (I) or (II)
- L is selected from alkylene and cycloalkylene groups having 1 to 10
carbon
atoms, suitably 2 to 6 carbon atoms and a bond if Y is a vinyl group; and/or
- K is selected from alkylene and cycloalkylene groups having 1 to 10
carbon
atoms, suitably 2 to 6 carbon atoms and a bond; and/or
Y is selected from an epoxy containing group, an amino group, a
polyamino group, an amido group, a thiol group, a carboxylic acid group, a
hydroxy group, a (meth)acryloxy group and a vinyl group; and/or
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- X is selected from alkoxy groups having suitably 1 to 4 carbon atoms;
and/or
- R is a Ci to C4 alkyl group; and/or
- B is a polyvalent alkyl group; and/or
n is 1, o is 0 and m is 3; and/or
- u is 1 and z is 2.
3. The coating composition of aspect 2, wherein the organo silane compound
is
selected from vinyl trialkoxysilane, 3-glycidoxypropyl trialkoxysilane,
3-(meth)acryloxypropyl trialkoxysilane, aminoalkyl trialkoxysilane, aminoalkyl
di
alkyl monoalkoxysilane, bis- (aminoalkyl) dialkoxysilane, thiolalkyl
trialkoxysilane, thiolalkyl alkyl dialkoxysilane, thiolalkyl di alkyl
monoalkoxysilane, N- [3 ethylenediamine, f3-(3,4-
epoxycyclohexyl)ethyl trimethoxysilane and combinations thereof.
4. The coating composition of any of the preceding aspects, wherein the
amount of
the organo silane compound is 5 to 18 wt.-%, suitably 10 to 18 wt.-% based on
the
total weight of the intumescent coating composition.
5. The coating composition of any of the preceding aspects, wherein the
polyepoxy-
functional compound (al) comprises diglycidyl ether of bisphenol A, diglygidyl
ether of bisphenol F, an epoxy phenol novolac resin, an epoxy cresol novolac
resin,
epoxy functional acrylic resins, epoxy functional polyester or combinations
thereof
6. The coating composition of any of the preceding aspects, wherein the
beta-hydroxy
ester of (meth)acrylic acid (a2) is present and comprises a plurality of beta-
hydroxy
(meth)acrylic ester groups, resulting from the reaction of a polyepoxide,
selected
from diglycidyl ether of bisphenol A, diglygidyl ether of bisphenol F, an
epoxy
phenol novolac resin, an epoxy cresol novolac resin, epoxy functional acrylic
resins, epoxy functional polyester or combinations thereof with (meth)acrylic
acid,
suitably the beta-hydroxy ester of (meth)acrylic acid (a2) comprises the
product of
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the reaction of a polyepoxide with (meth)acrylic acid in an epoxy carboxylic
acid
equivalent ratio of 1:0.1 to 1:1.015.
7. The coating composition of any of the preceding aspects, wherein the
(meth)acrylate-functional compound (a3) is present and selected from
poly(meth)acrylates of 1,4-butanediol, neopentyl glycol, ethylene glycol, 1,2-
propanediol, 1,3-propanediol, 2,2,4-trimethy1-1,3-pentanediol, 1,6-hexanediol,
1,4-
cyclohexane dimethanol, para-xylene glycol, 1,4-cyclohexane diol,
trimethylolethane, trimethylolpropane, pentaerythritol and combinations
thereof.
8. The coating composition of any of the preceding aspects, wherein
component (a)
comprises
- 100 wt.-%, suitably 40 ¨ 95 wt.-% of the polyepoxy-functional compound
(al);
15 0 - 75 wt.-%, suitably 5 ¨ 60 wt.-% of the beta-hydroxy ester of
(meth)acrylic acid
(a2); and
0 ¨ 50 wt.-%, suitably 5 ¨ 30 wt.-% of the (meth)acrylate-functional compound
(a3) different from compound (a2), wherein the weight percentages are based on
the total weight of compounds (al), (a2) and (a3).
9. The coating composition of any of the preceding aspects, wherein the
component
(b) comprises
- a polyamine-functional compound suitably selected from an aliphatic
polyamine, an aromatic polyamine, poly(amine-amides), and combinations
thereof: or
- a polythiol-functional compound suitably selected from polysulfide
thiols,
polyether thiols, polyester thiols, pentaerythritol based thiols; or
- combinations thereof.
10. The coating composition of any of the preceding aspects, wherein the
equivalent
ratio of the combined epoxy groups and (meth)acrylate groups in (a) to the
functional groups in (b) is from 2:1 to 1:2, suitably 1.3:1.0 to 1.0:1.3.
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11. The coating composition of any of the preceding aspects comprising
pigments
and/or fillers (e), wherein
- the total amount of white pigments and/or fillers selected from aluminum
oxides, silicon oxide, mica, wollastonite, titanium oxides, clay, talc, and
diatomaceous earth compounds is less than 2 wt.-%, suitably between 0-0.1
wt.-% based on the total weight of the composition, and
- the amount of colored pigments, particularly black pigments is at least
0.5
wt.-%, suitably between 1-5 wt.-% based on the total weight of the
composition.
12. The coating composition of any of the preceding aspects, further
comprising
additives (f) selected from a phoshorous source, a boron source, a zinc
source, an
acid source, a carbon source, rheology additives, organic solvents, pigments,
foam
stabilizers, adhesion promoters, corrosion inhibitors, UV stabilizers and
combinations thereof.
13. The coating composition of any of the preceding aspects, being a multi-
package
coating composition, wherein
component (a) is comprised in a first package (A) ;
component (b) is comprised in a second package (B);
compound (c) is comprised in a third package (C) or if Y- is a functional
group
reactive with the compounds in component (a) compound (c) is present in the
second package (B) or if Y- is a functional group reactive with the compounds
in
component (b) compound (c) is present in the first package (A)
the compound providing an expansion gas upon thermal decomposition (d) and any
of the additives (e) and (f) if present are comprised in any combination in
either
package (A), (B) or (C) or in any combination of theses packages or are
comprised
in one or more further packages (D); wherein the packages are mixed
immediately
prior to application of the coating composition.
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14. A method for coating a substrate comprising applying the intumescent
coating
composition according to any of aspects 1-13 at least partially to a substrate
and
optionally curing the applied coating composition.
15. The method of aspect 14, wherein the substrate comprises a metal
substrate,
suitably selected from aluminum and steel substrates or plastic substrate
suitably
selected from polycarbonate.
16. A substrate coated by the method of any of aspects 14 or 15.
17. An article comprising the substrate of aspect 16.
18. The article of aspect 17 being a battery suitably a lithium ion battery
or a battery
case.
19. The article of aspect 17 comprising a battery, suitably a lithium ion
battery or a
battery case, wherein the intumescent coating composition as defined in any of
aspects 1 ¨ 13 is applied to a part of the article adjacent to the battery
between the
battery and the article.
20. The article of aspect 17, wherein the article is a vehicle comprising a
lithium ion
battery or a battery case with sets of batteries and a passenger cabin and the
intumescent coating composition is applied to at least a part of the floor
portion of
the vehicle adjacent to the battery between the battery and the vehicle body.
21. Use of the intumescent coating composition of any of aspects 1 ¨ 13
to provide fire protection for a battery or a battery case and/or to reduce or
prevent thermal runaway of a battery or a battery case when applied to any
part of the battery or the battery case; or
to provide fire protection for an article comprising a battery when applied
to a part of the article adjacent to the battery between the battery and the
article,
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wherein the battery is suitably a lithium ion battery.
22. Use of aspect 21, wherein the article is a vehicle comprising a lithium
ion battery
and a passenger cabin and the curable intumescent coating composition is used
to
protect the passenger cabin of the vehicle from a battery fire.
23. A method to provide fire protection to a battery or to reduce or
prevent thermal
runaway of a battery by applying the intumescent coating composition of any of
aspects 1 ¨ 13 to any part of the battery to form a coating thereon, wherein
the
battery is suitably a lithium ion battery.
24. A method to provide fire protection for an article comprising a battery
by applying
the intumescent coating composition of any of aspects 1 ¨ 13 to a part of the
article
adjacent to the battery between the battery and the article to form a coating
thereon.
25. The method of aspect 24, wherein the article is a vehicle comprising a
lithium ion
battery and a passenger cabin and the crosslinked intumescent coating is
positioned
to protect the passenger cabin of the vehicle from a battery fire.
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The following examples are intended to be illustrative of the invention and
are not
intended to be limiting.
Examples:
Example 1
Following base and hardener components were combined and thoroughly mixed:
Base:
Component Parts by weight
Bisphenol A epoxy resin' 55
1,4-butanediol diglycidyl ether 21.5
Amide wax2 1.6
Pentaerythritol 15.7
Carbon black3 6.2
Hardener:
Component Parts by weight
Polyamide amine4 1.7
Isophorone diamine 3.1
Tall oil fatty acid5 4.4
Benzyl alcohol 7.9
Ammonium polyphosphate6 49.5
Melamine 15.7
N43-(Trimethoxysilyppropyl]ethylenediamine 17.7
EPON 828 Hexion Specialty Chemicals BV Vondelingenweg 601, 3196 KK
Vondelingenplaat, The
Netherlands
2 CRAYVALLAC ULTRA Arkema Inc., Europaweg Zuid 2,4389 PD Ritthem
The Netherlands
3 LAMP BLACK 101 Evonik Industries, Rellinghauser Stralk 1 ¨ 11, Essen,
45128, Germany
4_ARADUR 140, Huntsman, Dalenstraat 33, 3020 Winksele, Belgium
5 TALL OIL FATTY ACID Georgia-Pacific Nederland B.V., Teleportboulevard
140, 1043 EJ
Amsterdam. The Netherlands
6 CLARIANT AP 422 Clariant, IndustriestraBe, 50354 Hindi. Germany
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The mixture was spray applied to an aluminum panel (type 5005 H24) with 0.8 mm
thickness and allowed to cure at 23 C for a minimum of seven days. The dry
coating
thickness of the cured coating was 150 [tm.
On the back of the coated sample, a thermocouple was attached at the center
point to
monitor the temperature through the sample. The center of the coated panel was
then
positioned at a distance of 4 cm from a propane torch (diameter 3.5 cm,
propane) with the
crosslinked intumescent coating in the direction to the torch. The temperature
of the flame
was monitored through a second thermocouple placed close to the base of the
flame and
found to remain stable between 900-1000 C. The temperature at the back of the
coated
substrate was measured for a prolonged period of time. The result is shown in
Fig. 1.
Example 2
Example 1 was repeated, with the exception that the following base and
hardener
formulations were used:
Base:
Component Parts by weight
Bisphenol A epoxy resin' 67.0
1,4-butanediol diglycidyl ether 26.2
Amide wax2 0.3
Pentaerythritol 2.7
Carbon black' 3.8
Hardener:
Component Parts by weight
Polyamide amine4 24.2
Isophorone diamine 7.4
Polyoxypropylenediamine7 4.9
Tall oil fatty acid5 10.7
Benzyl alcohol 19.3
Ammonium polyphosphate6 17.1
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Melamine 5.4
N43-(Trimethoxysilyppropyl]ethylenediamine 11.0
7 JEFFAMINE D-230, Huntsman
The result is shown in Fig.2.
Example 3
Example 1 was repeated, with the exception that the following base and
hardener
formulations were used:
Base:
Component Parts by weight
Bisphenol A epoxy resin' 64.7
Amide wax2 0.6
Pentaerythritol 8.3
f3-(3,4-epoxycyclohexyl)ethyltrimethoxysilane 22.0
Carbon black3 4.4
Hardener:
Component Parts by weight
0,0'-Bis(2-aminopropyl) polypropylene glycol-block- 46.5
polyethylene glycol-block-polypropylene g1yco18
Tall oil fatty acid5 4.9
Benzyl alcohol 9.3
Ammonium polyphosphate6 29.9
Melamine 9.4
8 JEFFAMINE ED-600, Huntsman
The result is shown in Fig.3.
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Example 4:
Mix ratio (wt): Base/Hardener = 45.7/54.3
Silane content (wt%) in the total composition: 11.62 wt%
Base:
Component Parts by weight
Bisphenol A epoxy resin 86.0
Amide wax2 0.6
Pentaerythritol 9.1
Carbon black3 4.3
Hardener:
Component Parts by weight
0,0'-Bis(2-aminopropyl) polypropylene
glycol-block-polyethylene glycol-block- 11.1
polypropylene glycol
Tall oil fatty acid5 8.5
Benzyl alcohol 14.9
Ammonium polyphosphate6 33.5
Melamine 10.6
N43-(Trimethoxysilyppropyl]ethylenediamine 21.4
Example 5:
Mix ratio (wt): Base/Hardener = 44.8/55.2
Silane content (wt%) in the total composition: 9.11 wt%
Base:
Component Parts by weight
Bisphenol A epoxy resin" 86.0
Amide wax2 0.6
Pentaerythritol 9.1
Carbon black3 4.3
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Hardener:
Component Parts by weight
0,0'-Bis(2-aminopropyl) polypropylene
glycol-block-polyethylene glycol-block- 18.1
polypropylene g1yco18
Tall oil fatty acid5 8.3
Benzyl alcohol 14.5
Ammonium polyphosphate6 32.4
Melamine 10.2
N43-(Trimethoxysilyppropyl]ethylenediamine 16.5
Example 6:
Mix ratio (wt): Base/Hardener = 44.1/55.9
Silane content (wt%) in the total composition: 6.82 wt%
Base:
Component Parts by weight
Bisphenol A epoxy resin' 86.0
Amide wax2 0.6
Pentaerythritol 9.1
Carbon black3 4.3
Hardener:
Component Parts by weight
0,0'-Bis(2-aminopropyl) polypropylene
glycol-block-polyethylene glycol-block- 24.4
polypropylene g1yco18
Tall oil fatty acid5 8.0
Benzyl alcohol 14.0
Ammonium polyphosphate6 31.4
Melamine 9.9
N43-(Trimethoxysilyppropyl]ethylenediamine 12.2
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Example 7 (Comparative):
Mix ratio (wt): Base/Hardener = 43.2/56.8
Silane content (wt%) in the set: 4.17 wt%
Base:
Component Parts by weight
Bisphenol A epoxy resin 86.0
Amide wax2 0.6
Pentaerythritol 9.1
Carbon black 4.3
Hardener:
Component Parts by weight
0,0'-Bis(2-aminopropyl) polypropylene
glycol-block-polyethylene glycol-block- 31.4
polypropylene glycol
Tall oil fatty acid 7.7
Benzyl alcohol 13.5
Ammonium polyphosphate 30.4
Melamine 9.6
N43-(Trimethoxysilyppropyl]ethylenediamine 7.4
Example 8 (Comparative):
Mix ratio (wt): Base/Hardener = 42.5/57.5
Silane content (wt%) in the total composition: 2.01 wt%
Base:
Component Parts by weight
Bisphenol A epoxy resin' 86.0
Amide wax2 0.6
Pentaerythritol 9.1
Carbon black3 4.3
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Hardener:
Component Parts by weight
0,0'-Bis(2-aminopropyl) polypropylene
glycol-block-polyethylene glycol-block- 37.0
polypropylene g1yco18
Tall oil fatty acid5 7.5
Benzyl alcohol 13.2
Ammonium polyphosphate6 29.5
Melamine 9.3
N43-(Trimethoxysilyppropyl]ethylenediamine 3.5
Example 9 (Comparative)
Mix ratio (wt): Base/Hardener = 42.1/57.9
Silane content (wt%) in the set: 0.81 wt%
Base:
Component Parts by weight
Bisphenol A epoxy resin' 86.0
Amide wax2 0.6
Pentaerythritol 9.1
Carbon black3 4.3
Hardener:
Component Parts by weight
0,0'-Bis(2-aminopropyl) polypropylene
glycol-block-polyethylene glycol-block- 40.1
polypropylene g1yco18
Tall oil fatty acid5 7.4
Benzyl alcohol 12.9
Ammonium polyphosphate6 29.0
Melamine 9.2
N43-(Trimethoxysilyppropyl]ethylenediamine 1.4
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The intumescent coating compositions of examples 4 to 9 were applied to
aluminum
panels and tested as described for example 1. The results are shown in Fig.4.
41
